SNH4a Parapet – High-Containment Steel Safety Barrier

The SNH4a Parapet is a robust, modular vehicle restraint system (VRS) engineered for high-containment applications on motorways, trunk roads, and bridge structures. Designed and crash-tested to EN 1317 standards, the SNH4a delivers H4a containment level, W3 working width, and Impact Severity Level B, ensuring maximum roadside safety in high-risk areas. Constructed from steel posts, rails, deformation brackets, and rail joints, the system is bolted together using M16 galvanized fixings and secured with M27 stainless-steel holding-down bolts into cast-in or resin-bonded anchors.

SNH4a Parapet Advantages:

✔ H4a Containment Level – Engineered for high-containment applications
✔ Crash-Tested to EN 1317 – Tested to BS EN 1317-1:2010 and BS EN 1317-2:2010
✔ Modular & Durable Steel Construction – Ensures long-term performance
✔ W3 Working Width & Impact Severity Level B – Provides efficient energy absorption while minimizing impact forces
✔ Standard Post Spacing: 4500mm – Optimized for structural stability
✔ Secure Foundation System – Designed for cast-in or resin-bonded anchors
✔ Plinth Requirements:

  • Minimum width: 590mm
  • Traffic face upstand: 50mm (minimum) to 100mm (maximum)
Why Choose the SNH4a Parapet?

🔹 Designed for High-Risk Locations – Suitable for motorways, bridges, and high-speed road networks
🔹 Strong & Resilient Steel Construction – Provides long-term durability and impact resistance
🔹 Compliant with UK Highway Standards – Designed to meet National Highways specifications
🔹 Modular & Easy to Install – Simplified assembly using standardized fixings and anchors

The SNH4a Parapet is the ultimate choice for high-containment roadside safety solutions, offering superior protection in demanding environments.

Product Specifications - Overview/ Drawing
General Name Containment level Working width Type Installation condition Aesthetics
SNH4a H4a W3 Single-sided Anchored Box Profile
Product Catalogue
For more Technical Details visit our Product Catalogue.